On ma, 2016-08-01 at 10:10 +0100, Chris Wilson wrote:
> In order to prevent a leak of the vma on shared objects, we need to
> hook into the object_close callback to destroy the vma on the object for
> this file. However, if we destroyed that vma immediately we may cause
> unexpected application stalls as we try to unbind a busy vma - hence we
> defer the unbind to when we retire the vma.
>
> v2: Keep vma allocated until closed. This is useful for a later
> optimisation, but it is required now in order to handle potential
> recursion of i915_vma_unbind() by retiring itself.
> v3: Comments are important.
>
> Testcase: igt/gem_ppggtt/flink-and-close-vma-leak
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx>
Already added to previous series;
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_drv.c | 1 +
> drivers/gpu/drm/i915/i915_drv.h | 4 +-
> drivers/gpu/drm/i915/i915_gem.c | 88 ++++++++++++++++++-----------------
> drivers/gpu/drm/i915/i915_gem_evict.c | 8 +---
> drivers/gpu/drm/i915/i915_gem_gtt.c | 25 ++++++++++
> drivers/gpu/drm/i915/i915_gem_gtt.h | 1 +
> 6 files changed, 77 insertions(+), 50 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 478e8168ad94..869baa6a5196 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -2574,6 +2574,7 @@ static struct drm_driver driver = {
> .postclose = i915_driver_postclose,
> .set_busid = drm_pci_set_busid,
>
> + .gem_close_object = i915_gem_close_object,
> .gem_free_object = i915_gem_free_object,
> .gem_vm_ops = &i915_gem_vm_ops,
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index a1c4c768c0c3..f470ea195253 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -3014,8 +3014,8 @@ struct drm_i915_gem_object *i915_gem_object_create(struct drm_device *dev,
> size_t size);
> struct drm_i915_gem_object *i915_gem_object_create_from_data(
> struct drm_device *dev, const void *data, size_t size);
> +void i915_gem_close_object(struct drm_gem_object *gem, struct drm_file *file);
> void i915_gem_free_object(struct drm_gem_object *obj);
> -void i915_gem_vma_destroy(struct i915_vma *vma);
>
> /* Flags used by pin/bind&friends. */
> #define PIN_MAPPABLE (1<<0)
> @@ -3048,6 +3048,8 @@ int __must_check i915_vma_unbind(struct i915_vma *vma);
> * _guarantee_ VMA in question is _not in use_ anywhere.
> */
> int __must_check __i915_vma_unbind_no_wait(struct i915_vma *vma);
> +void i915_vma_close(struct i915_vma *vma);
> +void i915_vma_destroy(struct i915_vma *vma);
>
> int i915_gem_object_unbind(struct drm_i915_gem_object *obj);
> int i915_gem_object_put_pages(struct drm_i915_gem_object *obj);
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 3ebbeb4e0a24..74d24d7e3ca2 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -2596,6 +2596,19 @@ out_rearm:
> }
> }
>
> +void i915_gem_close_object(struct drm_gem_object *gem, struct drm_file *file)
> +{
> + struct drm_i915_gem_object *obj = to_intel_bo(gem);
> + struct drm_i915_file_private *fpriv = file->driver_priv;
> + struct i915_vma *vma, *vn;
> +
> + mutex_lock(&obj->base.dev->struct_mutex);
> + list_for_each_entry_safe(vma, vn, &obj->vma_list, obj_link)
> + if (vma->vm->file == fpriv)
> + i915_vma_close(vma);
> + mutex_unlock(&obj->base.dev->struct_mutex);
> +}
> +
> /**
> * i915_gem_wait_ioctl - implements DRM_IOCTL_I915_GEM_WAIT
> * @dev: drm device pointer
> @@ -2803,26 +2816,32 @@ static int __i915_vma_unbind(struct i915_vma *vma, bool wait)
> if (active && wait) {
> int idx;
>
> + /* When a closed VMA is retired, it is unbound - eek.
> + * In order to prevent it from being recursively closed,
> + * take a pin on the vma so that the second unbind is
> + * aborted.
> + */
> + vma->pin_count++;
> +
> for_each_active(active, idx) {
> ret = i915_gem_active_retire(&vma->last_read[idx],
> &vma->vm->dev->struct_mutex);
> if (ret)
> - return ret;
> + break;
> }
>
> + vma->pin_count--;
> + if (ret)
> + return ret;
> +
> GEM_BUG_ON(i915_vma_is_active(vma));
> }
>
> if (vma->pin_count)
> return -EBUSY;
>
> - if (list_empty(&vma->obj_link))
> - return 0;
> -
> - if (!drm_mm_node_allocated(&vma->node)) {
> - i915_gem_vma_destroy(vma);
> - return 0;
> - }
> + if (!drm_mm_node_allocated(&vma->node))
> + goto destroy;
>
> GEM_BUG_ON(obj->bind_count == 0);
> GEM_BUG_ON(!obj->pages);
> @@ -2855,7 +2874,6 @@ static int __i915_vma_unbind(struct i915_vma *vma, bool wait)
> }
>
> drm_mm_remove_node(&vma->node);
> - i915_gem_vma_destroy(vma);
>
> /* Since the unbound list is global, only move to that list if
> * no more VMAs exist. */
> @@ -2869,6 +2887,10 @@ static int __i915_vma_unbind(struct i915_vma *vma, bool wait)
> */
> i915_gem_object_unpin_pages(obj);
>
> +destroy:
> + if (unlikely(vma->closed))
> + i915_vma_destroy(vma);
> +
> return 0;
> }
>
> @@ -3043,7 +3065,7 @@ i915_gem_object_bind_to_vm(struct drm_i915_gem_object *obj,
>
> if (offset & (alignment - 1) || offset + size > end) {
> ret = -EINVAL;
> - goto err_free_vma;
> + goto err_vma;
> }
> vma->node.start = offset;
> vma->node.size = size;
> @@ -3055,7 +3077,7 @@ i915_gem_object_bind_to_vm(struct drm_i915_gem_object *obj,
> ret = drm_mm_reserve_node(&vm->mm, &vma->node);
> }
> if (ret)
> - goto err_free_vma;
> + goto err_vma;
> } else {
> if (flags & PIN_HIGH) {
> search_flag = DRM_MM_SEARCH_BELOW;
> @@ -3080,7 +3102,7 @@ search_free:
> if (ret == 0)
> goto search_free;
>
> - goto err_free_vma;
> + goto err_vma;
> }
> }
> if (WARN_ON(!i915_gem_valid_gtt_space(vma, obj->cache_level))) {
> @@ -3101,8 +3123,7 @@ search_free:
>
> err_remove_node:
> drm_mm_remove_node(&vma->node);
> -err_free_vma:
> - i915_gem_vma_destroy(vma);
> +err_vma:
> vma = ERR_PTR(ret);
> err_unpin:
> i915_gem_object_unpin_pages(obj);
> @@ -4051,21 +4072,18 @@ void i915_gem_free_object(struct drm_gem_object *gem_obj)
>
> trace_i915_gem_object_destroy(obj);
>
> + /* All file-owned VMA should have been released by this point through
> + * i915_gem_close_object(), or earlier by i915_gem_context_close().
> + * However, the object may also be bound into the global GTT (e.g.
> + * older GPUs without per-process support, or for direct access through
> + * the GTT either for the user or for scanout). Those VMA still need to
> + * unbound now.
> + */
> list_for_each_entry_safe(vma, next, &obj->vma_list, obj_link) {
> - int ret;
> -
> + GEM_BUG_ON(!vma->is_ggtt);
> + GEM_BUG_ON(i915_vma_is_active(vma));
> vma->pin_count = 0;
> - ret = __i915_vma_unbind_no_wait(vma);
> - if (WARN_ON(ret == -ERESTARTSYS)) {
> - bool was_interruptible;
> -
> - was_interruptible = dev_priv->mm.interruptible;
> - dev_priv->mm.interruptible = false;
> -
> - WARN_ON(i915_vma_unbind(vma));
> -
> - dev_priv->mm.interruptible = was_interruptible;
> - }
> + i915_vma_close(vma);
> }
> GEM_BUG_ON(obj->bind_count);
>
> @@ -4129,22 +4147,6 @@ struct i915_vma *i915_gem_obj_to_ggtt_view(struct drm_i915_gem_object *obj,
> return NULL;
> }
>
> -void i915_gem_vma_destroy(struct i915_vma *vma)
> -{
> - WARN_ON(vma->node.allocated);
> -
> - /* Keep the vma as a placeholder in the execbuffer reservation lists */
> - if (!list_empty(&vma->exec_list))
> - return;
> -
> - if (!vma->is_ggtt)
> - i915_ppgtt_put(i915_vm_to_ppgtt(vma->vm));
> -
> - list_del(&vma->obj_link);
> -
> - kmem_cache_free(to_i915(vma->obj->base.dev)->vmas, vma);
> -}
> -
> static void
> i915_gem_stop_engines(struct drm_device *dev)
> {
> diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
> index 81f7b4383d5e..3437ced76cb6 100644
> --- a/drivers/gpu/drm/i915/i915_gem_evict.c
> +++ b/drivers/gpu/drm/i915/i915_gem_evict.c
> @@ -182,8 +182,8 @@ found:
> struct i915_vma,
> exec_list);
> if (drm_mm_scan_remove_block(&vma->node)) {
> + vma->pin_count++;
> list_move(&vma->exec_list, &eviction_list);
> - i915_gem_object_get(vma->obj);
> continue;
> }
> list_del_init(&vma->exec_list);
> @@ -191,18 +191,14 @@ found:
>
> /* Unbinding will emit any required flushes */
> while (!list_empty(&eviction_list)) {
> - struct drm_i915_gem_object *obj;
> -
> vma = list_first_entry(&eviction_list,
> struct i915_vma,
> exec_list);
>
> - obj = vma->obj;
> list_del_init(&vma->exec_list);
> + vma->pin_count--;
> if (ret == 0)
> ret = i915_vma_unbind(vma);
> -
> - i915_gem_object_put(obj);
> }
>
> return ret;
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index f5f563d0a1ce..e0a864ae9e0b 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -3335,6 +3335,31 @@ i915_vma_retire(struct i915_gem_active *active,
> return;
>
> list_move_tail(&vma->vm_link, &vma->vm->inactive_list);
> + if (unlikely(vma->closed && !vma->pin_count))
> + WARN_ON(i915_vma_unbind(vma));
> +}
> +
> +void i915_vma_destroy(struct i915_vma *vma)
> +{
> + GEM_BUG_ON(vma->node.allocated);
> + GEM_BUG_ON(i915_vma_is_active(vma));
> + GEM_BUG_ON(!vma->closed);
> +
> + list_del(&vma->vm_link);
> + if (!vma->is_ggtt)
> + i915_ppgtt_put(i915_vm_to_ppgtt(vma->vm));
> +
> + kmem_cache_free(to_i915(vma->obj->base.dev)->vmas, vma);
> +}
> +
> +void i915_vma_close(struct i915_vma *vma)
> +{
> + GEM_BUG_ON(vma->closed);
> + vma->closed = true;
> +
> + list_del_init(&vma->obj_link);
> + if (!i915_vma_is_active(vma) && !vma->pin_count)
> + WARN_ON(__i915_vma_unbind_no_wait(vma));
> }
>
> static struct i915_vma *
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
> index 674e118e3686..a3ea1bda2b1b 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.h
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
> @@ -189,6 +189,7 @@ struct i915_vma {
> #define LOCAL_BIND (1<<1)
> unsigned int bound : 4;
> bool is_ggtt : 1;
> + bool closed : 1;
>
> /**
> * Support different GGTT views into the same object.
--
Joonas Lahtinen
Open Source Technology Center
Intel Corporation
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